You need to use \! before shell command
Examples:
MariaDB [(none)]> \! date; Sun Sep 9 03:18:38 CEST 2018 MariaDB [(none)]> \! ls -d public_html; public_html MariaDB [(none)]> \! touch 1.txt MariaDB [(none)]> \! ls 1.txt 1.txt MariaDB [(none)]> \! uptime; 03:19:40 up 8 days, 11:45, 8 users, load average: 4.92, 5.07, 4.89 MariaDB [(none)]>